The invention relates to an airbag, in particular for a motor vehicle.
German Patent Publication DE 10 2007 052 264 A1 discloses an airbag for a motor vehicle, with a support structure that can be moved out of a storage position into a restraint position, and with a covering by means of which a restraint volume of the airbag, which is formed by the support structure in its restraint position, is surrounded.
Exemplary embodiments of the present invention are directed to an airbag having a reduced installation space requirement.
According to exemplary embodiments of the present invention, an airbag, in particular for a motor vehicle, comprises a support structure that can be moved out of a storage position into a restraint position. Further, the airbag comprises a covering by means of which a restraint volume of the airbag, which is formed by the support structure in its restraint position, is surrounded.
According to the invention, provision the covering is formed as an element that is separate from the support structure and has passage regions in which the covering is at least substantially permeable to air in at least one direction of flow, and connecting regions that are reinforced relative thereto and are optionally impermeable to air in which the covering is connected to the support structure. The covering thus represents a support for the support structure, to which the support structure is fastened. The covering makes it possible in this case a medium, in particular ambient air, upon the movement of the support structure or the airbag into the restraint position, to be able to flow particularly quickly in the one direction of flow through the covering into the restraint volume, so that the support structure with the covering in a particularly short time can occupy a particularly large volume in a passenger compartment of the motor vehicle, in order to be able to intercept, restrain and protect against serious injuries at least one occupant particularly well in the event of an accident-related application of force.
Further, the covering, in particular due to the connecting regions that are impermeable to air, which are formed reinforced relative to the passage regions, can absorb forces that are produced as a result of the accident-related application of force, in order advantageously to be able to restrain the or several occupants in the passenger compartment.
Due to the configurations of the passage regions and the connecting regions that differ from each other, the covering is non-homogeneous, and functions as a non-homogeneous support for the support structure, in which the passage regions and the connecting regions are formed according to requirements and are adapted to their respective purposes. This makes it possible to make the covering particularly thin, but at the same time particularly tear resistant. As a result of this, the covering and hence the entire airbag, in particular in the storage position, has an only very low installation space requirement, which results in package problems being solved or avoided. At the same time, the airbag according to the invention ensures particularly good protection of the occupant or occupants in the case of an accident-related application of force to the motor vehicle. Furthermore, due to the non-homogeneous configuration of the covering, the weight of the airbag can be kept low, which is of benefit for a low total weight of the motor vehicle and hence a low fuel consumption and low CO2 emissions.
In the passage regions, a respective valve functionality is advantageously provided by the covering. In other words, the covering in the passage regions has in each case at least one valve, in particular a tube valve. This valve makes it possible in this case for a medium, in particular ambient air, upon the movement of the support structure into the restraint position, to be able to flow through the covering with a particularly large mass stream in a particularly short time in the one direction of flow and to be able to flow into the restraint volume. Further, the valve or valves advantageously make(s) it possible at least substantially to avoid the medium, in particular the ambient air, flowing in a second direction of flow that is opposed to the one direction of flow through the covering out of the restraint volume, or to permit a mass stream of the medium, in particular the ambient air, in the second direction of flow out of the restraint volume, which is considerably less than a mass stream of the medium, in particular the ambient air, in the first direction of flow into the restraint volume.
If, for example, an occupant strikes the support structure and the covering, which is referred to as plunging, an internal pressure prevailing in the restraint volume is thereby increased, which would cause the medium, in particular the ambient air, to flow out of the restraint volume, this however being at least substantially prevented or slowed down by the valves. The at least substantial preventing or slowing down of the medium flowing out of the restraint volume ensures a particularly long and good service life of the support structure and the covering, so that the plunging occupant can be intercepted and restrained particularly well. Furthermore, the particularly long service life makes it possible to move the support structure and the covering into the restraint position particularly early and possibly even before the actual accident-related application of force to the motor vehicle, the support structure and the covering being for example unfolded from the storage position.
The support structure comprises, for example, a plurality of volume elements, in particular tube elements, the respective volumes of which can be enlarged. For this, the volume elements can be filled, in particular inflated, for example with a medium, in particular with a gas. As a result of acting upon the volume elements with the medium, for example by means of at least one pyrotechnic actuator, in particular a gas generator, the support structure is moved out of the storage position and unfolded, and in the restraint position takes up a particularly large volume in the passenger compartment. Advantageously, at least a partial amount of the volume elements are connected together fluidically to form a common duct system. This has the advantage that, as a result merely, one actuator, in particular a gas generator, is necessary in order to act upon the volume elements that are connected together fluidically with the medium, in particular gas, and thus to enlarge their respective volumes. Such a support structure in this case has the advantage that a total volume that is to be acted upon by the medium and that consists of the individual volumes of the respective tube elements is considerably less than the restraint volume formed by the support structure in its restraint position. This allows a particularly rapid movement of the support structure into the restraint position, so that it takes up a particularly large volume in the passenger compartment particularly early and thus can intercept and restrain the occupant particularly well. Moreover, the support structure can thereby be moved into the restraint position in a particularly gentle and soft manner for the occupant.
In one advantageous embodiment of the invention, the covering is formed at least partially as a fabric. In other words, the covering comprises at least one fabric layer, the fabric or the fabric layer in the connecting regions having a greater thread density and/or a greater thread size compared with the passage regions. The connecting regions can thereby assume a load-bearing function and ensure a high tear strength of the covering, whereas the passage regions advantageously permit rapid flowing of the medium into the restraint volume and a long service life of the airbag.
The fabric or the fabric layer of the covering in this case is formed to be advantageously permeable to air, so that the medium, in particular the ambient air, can flow particularly well and rapidly into the restraint volume. In this case, the covering comprises, for example, a further layer, in particular a sheet, which permits flowing of the medium in the one direction of flow into the restraint volume and at least substantially prevents flowing of the medium in the direction of flow opposed to the one direction of flow, or slows it down relative to the flowing in the one direction of flow. The sheet forms, for example, the tube valves, which collapse as a result of the increase in the internal pressure in the restraint volume, at least substantially close passage openings of the sheet or reduce a passage cross section of the passage openings and thus at least substantially prevent the medium, in particular the ambient air, flowing in the second direction of flow out of the restraint volume, or slow it down relative to the flowing in the one direction of flow. The fabric or the fabric layer of the covering in this case has the further function of providing puncture protection, so that the sheet or the tube valves do not puncture and unwantedly turn inside out, which would result in undesirable valve functionality that would be contrary to the valve functionality described.
Further advantages, features and details of the invention will become apparent from the following description of a preferred example of embodiment and with reference to the drawings. The features and combinations of features mentioned above in the description and the features and combinations of features mentioned below in the description of the figures and/or shown in the figure alone are not only usable in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the invention.